Dibenzofuryl-benzoxazolyl-styrenes

ABSTRACT

THE INVENTION RELATES TO NEW DIBENZOFURAN COMPOUNDS, WHICH ARE SUBSTITUTED IN POSITION 2 OR 3 WITH A BENZOXAZOLYL-STYRYL RESIDUE AND WHEREIN THE BENZOXAZOLYL MOIETY MAY BE FURTHER SUBTITUTED WITH NON-CHROMOPHORIC SUBSTITUENTS. THE COMPOUNDS ARE USEFUL AS FLUORESCENT WHITENING AGENTS ESPECIALLY FOR SPINNING MASSES OF SYNTHETIC ORGANIC MATERIALS.

United States Patent 3,796,707 DIBENZOFURYL-BENZOXAZOLYL-STYRENES Adolf Emil Siegrist, Basel, and Jacques Garmatter, Bern,

Switzerland, assignors to Ciba-Geigy AG, Basel, Switzerland No Drawing. Filed Sept. 14, 1972, Ser. No. 289,185 Int. Cl. C07d /44 US. Cl. 260-240 D 4 Claims ABSTRACT OF THE DISCLOSURE The invention relates to new dibenzofuran compounds, which are substituted in position 2 or 3 with a benzoxazolyl-styryl residue and wherein the benzoxazolyl moiety may be further substituted with non-chromophoric substituents.

The compounds are useful as fluorescent whitening agents, especially for spinning masses of synthetic organic materials.

wherein R denotes hydrogen, alkyl with 1 to 8 carbon atoms, phenylalkyl with 1 to 4 carbon atoms in the alkyl part, phenyl, cyclohexyl, nitrile, benzyloxy, phenoxy, chlorine, sulphonic acid monoalkylamide or dialkylamide with 1 to 8 carbon atoms in the alkyl part, phenylsulphone or 1 to 4 C-alkylsulphone, R denotes hydrogen or alkyl with 1 to 5 carbon atoms or alkoxy with 1 to 4 carbon atoms and n represents the numbers 1 or 2.

As can be seen, the above formula is to be understood to imply that the benzoxazolyl-styryl radical can occupy either position 2 or position 3 in the dibenzofurane.

Preferred compounds are those in which the benzoxazolyl-styryl radical occupies position 3, that is to say compounds of the formula wherein R denotes hydrogen, alkyl with 1 to 8 carbon atoms, phenylalkyl with 1 to 4 carbon atoms in the alkyl part, phenyl, cyclohexyl, akoxy with 1 to 4 carbon atoms, benzyloxy, phenoxy, chlorine, sulphonic acid monoalkylamide or dialkylamide with 1 to 8 carbon atoms in the alkyl part, phenylsulphone or 1 to 4 C-alkylsulphone, R denotes hydrogen or alkyl with 1 to 5 carbon atoms and n represents the numbers 1 or 2.

Within the scope of the above definitions, styryl com- 3,796,707 Patented Mar. 12, 1974 ice pounds of preferred practical interest are those which correspond to the formula wherein R is in positions 5 or 6 of the benzoxazolyl radical and denotes hydrogen, alkyl with 1 to 8 carbon atoms, cyclohexyl, phenyl, phenylalkyl with l to 4 carbon atoms in the alkyl part, alkoxy with 1 to 4 carbon atoms, phenoxy or halogen and R represents hydrogen or alkyl with 1 to 4 carbon atoms.

The new compounds according to the present invention can be manufactured analogously to processes which are in themselves known.

An appropriate manufacturing method for the manufacture of compounds of the Formula 1 consists, for example, of reacting an aldehyde of the formula wherein the aldehyde group occupies positions 2 or 3, with a phosphorus compound of the formula wherein R R and n have the above-mentioned meaning and R represents an alkyl group with 1 to 6 carbon atoms, phenyl or benzyl.

The aldehydes according to the Formula 5 are obtainable as follows: dibenzofurane-2-carbaldehyde is obtained by the Gattermann method from dibenzofurane, aluminium chloride, hydrogen cyanide and hydrochloric acid. Dibenzofurane-3-carbaldehyde is produced by reduction of 3-cyano-dibenzofurane with neutral Raney nickel in glacial acetic acid-pyridine-water and sodium hypophosphite.

The phosphorus compounds according to the Formula 6 are obtained, for example, by reaction of the corresponding bromomethyl or chloromethyl compounds with trialkyl phosphites.

The manufacturing process is advantageously carried out in polar, aprotic, organicsolvents such as dimethylformamide and dimethylsulphoxide at temperatures of between 20 and 60 C. and in the presence of strongly basic alkali compounds, such as hydroxides, amides and alcoholates (preferably alcoholates of primary alcohols containing 1 to 4 carbon atoms) of the alkali metals.

A different method of manufacture of practical interest-especially for the manufacture of compounds according to the Formula 2 and subordinate formulae--consists in applying the anil synthesis method. According to this, a Schiifs base of the formula wherein h represents hydrogen or chlorine, is reacted with a methyl compound of the formula the reaction being carried out in dimethylformamide as the reaction medium and in the presence of a strongly basic alkali compound.

A strongly basic alkali compound is required for this reaction. By such compounds there are to be understood compounds of the alkali metals (main Group I of the Periodic System of the Elements) including ammonium compounds, which have a basic strength of at least approximately that of lithium hydroxide. They can accordingly be compounds of lithium, sodium, rubidium, caesium or ammonium of the type of, for example, alcoholates, hydroxides, amides, hydrides and sulphides, or strongly basic ion exchangers. It is advantageous (above all if mild reaction conditions as regards reaction temperature appear to be indicated) to use potassium compounds of the composition wherein 2: represents an integer from 1 to 6, such as, for example, potassium hydroxide or potassium tert.butylate. In the case of alkali alcoholates and alkali amides (and hydrides) the reaction should be carried out in a practically anhydrous medium, whilst in the case of alkali hydroxides water contents of up to 25% (for example the presence of water of crystallization) are permitted. In the case of potassium hydroxide, a water content of up to about has proved appropriate. As examples of other alkali metal compounds which can be used there may be mentioned: sodium methylate, sodium hydroxide, sodium amide, lithium amide, lithium hydroxide, rubidium hydroxide or caesium hydroxide. Of course it is also possible to use mixtures of such bases.

Appropriately, the compounds of the type of the Formula 8 are reacted with the aldehyde-anils in equivalent amounts, so that there is not a significant excess of either component present. Advantageously, at least the equivalent amount of the alkali compound is used, that is to say at least 1 mol of a compound with, for example, a KO group, per 1 mol of aldehyde-anil. If potassium hydroxide is used, a 4-fold to 8-fold amount is preferably employed.

The reaction according to the invention can generally be carried out at temperatures in the range of between about 10 and 150 C. If alcoholates are used as the potassium compound in the reaction, the reaction frequently already takes place at room temperature, in which case no external application of heat is necessary. If potassium hydroxide is used, it is in most cases necessary to work at an elevated temperature. For example, the reaction mixture is slowly warmed to 30100 C. and is then kept for some time, for example /2 to 2 hours, at this temperature. The final substances can be workedup from the reaction mixture in accordance with customary methods which are in themselves known.

The new compounds defined above show a more or less pronounced fluorescence in the dissolved or finely divided state. They can be used for the optical brightening of the most diverse synthetic or semi-synthetic organic materials, or substances which contain such organic materials.

The following groups of organic materials, where optical brightening thereof is relevant, may be mentioned as examples of the above, without the survey given below being intended to express any restriction thereto.

(1) Synthetic organic high molecular materials:

(a) Polymerization products based on organic compounds containing at least one polymerizable carboncarbon double bond, that is to say their homopolymers or copolymers as well as their after-treatment products such as, for example, crosslinking, grafting or degradation products, polymer blends, products obtained by modification of reactive groups, for example polymers based on il-unsaturated carboxylic acids or derivatives of such carboxylic acids, especially on acrylic compounds (such as, for example, acrylic esters, acrylic acid, acrylonitrile, acrylamides and their derivatives or their methacryl analogues), on olefine hydrocarbons (such as, for example, ethylene, propylene, styrenes or dienes and also so-called ABS polymers), and polymers based on vinyl and vinylidene compounds (such as, for example, vinyl chloride, vinyl alcohol or vinylidene chloride),

(b) Polymerization products such as are, for example, obtainable by ring opening, for example polyamides of the polycaprolactam type, and also polymers which are obtainable both via polyaddition and via polycondensation, such as polyethers or polyacetals,

(c) Polycondensation products or precondensates based on bifunctional or polyfunctional compounds possessing condensable groups, their homocondensation and co-condensation products, and after-treatment products, such as, for example, polyesters, especially saturated (for example ethylene glycol terephthalic acid polyesters) or unsaturated (for example maleic acid dialcohol polycondensates as well as their crosslinking products with copolymerizable vinyl monomers), unbranched or branched (also based on high-functional alcohols, such as, for example, alkyd resins) polyesters, polyamides (for example hexamethylenediamine adipate), maleate resins, melamine resins, their precondensates and analogues, polycarbonates and silicones,

(d) Polyaddition products such as polyurethanes (crosslinked and non-crosslinked) and epoxide resins.

(II) Semi-synthetic organic materials, for example, cellulose esters of varying degrees of esterification (socalled ZVz-acetate or triacetate) or cellulose ethers regenerated cellulose (viscose or cuprammonium cellulose), or their after-treatment products, and casein plastics.

The organic materials to be optically brightened can be in the most diverse states of processing (raw materials, semi-finished goods or finished goods). On the other hand, they can be in the form of structures of the most diverse shapes, that is to say, for example, as predominantly three-dimensional bodies such as sheets, profiles, injection mouldings, various machined articles, chips, granules or foams, and also as predominantly two-dimensional bodies such as films, foils, lacquers, coatings, impregnations and coatings, or as predominantly onedimensional bodies such as filaments, fibres, flocks and wires. The said materials can, on the other hand, also be in an unshaped state, in the most diverse homogeneous or inhomogeneous forms of division, such as, for example, in the form of powders, solutions, emulsions, dispersions, latices, pastes or waxes.

Fibre materials can, for example, be in the form of endless filaments (stretched or unstretched), staple fibers, flocks, hanks, textile filaments, yarns, threads, fibre fleeces, felts, waddings, flock structures or woven textile fabrics, textile laminates, knitted fabrics and papers, cardboards or paper pulps.

The compounds to be used according to the invention are of importance, inter alia, for the treatment of organic textile materials, especially woven textile fabrics.

Where fibres, which can be in the form of staple fibres or endless filaments or in the form of hanks, woven fabrics, knitted fabrics, fleeces, flock substrates or laminates, are to be optically brightened according to the invention, this is advantageously effected in an aqueous medium, wherein the compounds in question are present in a finely divided form (suspensions, so-called microdispersions or possibly solutions). If desired, dispersing agents, stabilizers, wetting agents and further auxiliaries can be added during the treatment.

Depending on the type of brightener compound used, it may prove advantageous preferably to carry out the treatment in a neutral or alkaline or acid bath. The treatment is usually carried out at temperatures of about 20 to 140 C., for example at the boiling point of the bath or near it (about 90 C.). Solutions or emulsions in organic solvents can also be used for the finishing, according to the invention, of textile substrates, as is practised in the dyeing trade in so-called solvent dyeing (pad-thermofix application, or exhaustion dyeing processes in dyeing machines).

The new optical brighteners according to the present invention can further be added to, or incorporated in, the materials before or during their shaping. Thus, they can for example be added to the compression moulding composition or injection moulding composition during the manufacture of films, sheets (for example milling into hot polyvinyl chloride) or mouldings.

Where fully synthetic or semi-synthetic organic materials are being shaped by spinning processes or via spinning compositions, the optical brighteners can be applied in accordance with the following processes:

Addition to the starting substances (for example monomers) or intermediates (for example precondensates or prepolymers), that is to say before or during the polymerization, polycondensation or poly-addition,

Powdering onto polymer chips or granules for spinning compositions,

Bath dyeing of polymer chips or granules for spinning compositions,

Metered addition to spinning melts or spinning solutions, and

Application to the two before stretching.

The new optical brighteners according to the present invention can, for example, also be employed in the following use forms:

(a) Mixed with dyestuffs (shading) or pigments (colored or, especially, for example, white pigments),

(b) Mixed with so-called carriers, wetting agents, plasticizers, swelling agents, anti-oxidants, light protection agents, heat stabilizers and chemical bleaches (chlorite bleach and bleach bath additives),

(0) Mixed with crosslinking agents or finishes (for examples starch or synthetic finishes), and in combination with the most diverse textile finishing processes, especially flame-proof finishes, soft handle finishes, anti-soiling finishes or antistatic finishes, or antimicrobial finishes,

(d) Incorporation of the optical brighteners into polymeric carriers (polymerization, polycondensation or polyaddition products), in a dissolved or dispersed form, for use, for example, in coating compositions, impregnating compositions or binders (solutions, dispersions and emulsions) for textiles, fleeces, paper and leather,

(e) As additives to so-called master batches,

(f As additives to the most diverse industrial products in order to render these more marketable (for example improving the appearance of soaps, detergents and pigments),

(g) In combination with other optically brightening substances,

(h) In spinning bath preparations, that is to say as additives to spinning baths such as are used for improving the slip for the further processing of synthetic fibres, or from a special bath before the stretching of the fibres,

(i) As scintillators for various photographic purposes, such as, for example, for electrophotographic reproduction, for the optical brightening of photographic layers, optionally in combination with white pigments such as, for example, T102, or for supersensitization.

If the brightening process is combined with textile treatment methods or finishing methods, the combined treatment can in many cases advantageously be carried out with the aid of appropriate stable preparations, which contain the optically brightening compounds in such concentration that the desired brightening effect is achieved.

In certain cases, the brighteners are made fully effective by an after-treatment. This can, for example, represent a chemical treatment (for example acid treatment), a thermal treatment (for example heat) or a combined chemical/ thermal treatment. Thus, for example, the appropriate procedure to follow in optically brightening a series of fibre substrates, for example polyester fibres with the brighteners according to the invention is to impregnate these fibres with the aqueous dispersions (or, where appropriate, solutions) of the brighteners at temperatures below 75 C., for example at room temperature, and to subject them to a dry heat treatment at temperatures above C., it being generally advisable additionally to dry the fibre material beforehand at a moderately elevated temperature, for example at not less than 60 C. and up to about 130 C. The heat treatment in the dry state is then advantageously carried out at temperatures between and 225 C., for example by heating in a drying chamber, by ironing within the specified temperature range or by treatment with dry, superheated steam. The drying and dry heat treatment can also be carried out in immediate succession or be combined in a single process stage.

The amount of the new optical brighteners to be used according to the invention, relative to the material to be optically brightened, can vary within wide limits. A distinct and durable eifect is already achievable with very small amounts, in certain cases, for example, amounts of 0.0001 percent by weight. However, amounts of up to about 0.8 percent by weight and at times up to about 2 percent by weight can also be employed. For most practical purposes, amounts between 0.001 and 0.5 percent by weight are of preferred interest.

In the examples, the parts, unless otherwise stated, are always parts by weight and the percentages are always percentages by weight. Unless otherwise stated, melting points and boiling points are uncorrected.

EXAMPLE 1 5.09 g. of the Schiifs base from dibenzofurane-3-carbaldehyde and p-chloroaniline, of the formula (melting point: 156 to 156-5 C.), 3.48 g. of 4-(benzoxazolyl-2-yl)-toluene of the formula theory, of (dibenzofuran 3-yl)-4-(benzoxazol-2-yl)- styrene of the formula listed in the table which follows can be manufactured similarly.

Melting point, N 0. R a Rs Rt, C

13- --CH8 H H 266-267 H CH3 H 259-260 15- H H CH! 220-221 16.... CH: -CH; H 291-292 17. -CHa H CH3 208-209 18---- -CH2CHI H H 250-251 19---- -CH2CHr-CH: H K 269-270 20- CH: H H 254-255 21...- CH) H H 256-257 I -CH| CHI 22..-. OH: H -CH: 218-219 -(i7CH:

23.... --CH: H CH; 253-254 24..-- (EH: (EH: H H 247-248 (E C H:- C- CH:

CH: CH]

CHr-Hz C H H 255-256 --CH CH2 CHz-HaC 26 Q E K 279-280 27.... H Q H 285-286 29.--- EH3 H H 232-233 Q CH:

30....- -OCHI H H 253-254 TABLEContinued Melting point,

No. R. R R, C.

32-.-- Cl H H 286-287 33...- Cl H CHs 227-228 The dibenzofurane-3-carbaldehyde (melting point 129 to 129.5 C.) used for the preparation of the Schiifs base of the Formula 9 can be obtained by reduction of 3-cyano-dibenzofurane with neutral Raney nickel in glacial acetic acid-pyridine-water and sodium hypophosphite at 50 to 55 C.

EXAMPLE 2 3.82 g. of the Schiffs base from dibenzofurane-3-carbaldehyde and p-chloroaniline, of the Formula 9, 3.78 g. of 4-(S-methylsulphamyl-benzoxazol-Z-yl)-toluene of the formula and 2.8 g. of potassium t-butylate in ml. of dimethylfor-mamide are stirred, with exclusion of air, for one hour at 20 to 25 C. Thereafter 400 ml. of methanol are added and the reaction mixture is cooled to 0 C. The product which has precipitated is filtered off, washed with ml. of methanol and dried. 4.3 g., corresponding to 71.1% of theory, of B-(dibenzofuran-3-yl)-4-(S-methylsulphamylbenzoxazol-Z-yl)-styrene of the formula 0 0 O CH=CH- -C listed in the table which follows can be manufactured similarly.

Melting point,

No; R C.

37- SOr-NHCH: 314-315 38 SO:NH(CH2)1CH: 238-239 9 EXAMPLE 3 3.1 g. of the Schiffs base from dibenzofurane-Z-carbaldehyde and p-chloroaniline, of the formula (melting point: 120 to 120.5" C.), 2.37 g. of 4-(5,6-dimethylbenzoxazol-Z-yl)-toluene of the formula HQQC and 2.6 g. of potassium hydroxide powder containing about 10% of water are reacted in 80 m1. of dimethylformamide in accordance with the instructions of Example 1.

2.8 g., corresponding to 67.5% of theory, of ,B-(dibenzofuran-Z-yl) 4 (5,6-dimethyl)-benzoxazol-2-yl)- styrene of the formula are obtained in the form of a light yellow powder of melting point 210 to 212 C. T-wo recrystallizations from toluene (fullers earth) yield 2.4 g. (57.8% of theory) of light, greenish-tinged yellow, very fine small needles which melt at 219 to 220 C.

Analysis.Calculated for C H NO (415.47) (percent): C, 83.83; H, 5.09; N, 3.37. Found (percent): C, 85.57; H, 5.07; N, 3.48.

The compounds of the formula (42) /0\ CH=CH C Q Q Q EXAMPLE 4 100 parts of polyester granules from terephthalic acid ethylene glycol polyester are intimately mixed with 0.05 part of one of the compounds of the Formulae 3 or 13 to 33 and the mixture is fused at 285 C., whilst stirring. After spinning the spinning composition through customary spinnerets, strongly brightened polyester fibres of good fastness to light are obtained.

The above-mentioned compounds can also be added to the starting substances before or during the polycondensation to give the polyester.

EXAMPLE 5 10,000 parts of granular polyamide-6 are mixed with 30 parts of titanium dioxide (rutile modification) and 2 parts of one of the compounds of the Formulae 11 or 13 to 33 in a tumbler vessel for 12 hours. The mixture is fused with exclusion of atmospheric oxygen and the melt is spun in the usual manner. The resulting filaments show a strong brightening efiect with good fastness to light.

If instead of polyamide-6 polyamide-66 is used, similarly strong brightening effects are obtained.

EXAMPLE 6 A polyester fabric (for example Dacron) is padded at room temperature (about 20 C.) with an aqueous dispersion which contains, per litre, 2 g. of one of the compounds of the Formulas 11, 13, 22, 27, 28 or 31 and 1 g. of an addition product of about 8 mols of ethylene oxide to 1 mol of p-tert.octylphenol, and is dried at about C. The dry material is subsequently subjected to a heat treatment at to 220 C. which lasts from 2 minutes to a few seconds, depending on the temperature. The material treated in this way has a substantially whiter ap pearance than the untreated material.

EXAMPLE 7 A polyamide fibre fabric (Perlon) is introduced, using a liquor ratio of 1:40, into a bath at 60 C. which contains (relative to the weight of the fabric) 0.1% of one of the brighteners of the Formulas 11, 13 or 22 and, per litre, 1 g. of 80% strength acetic acid and 0.25 g. of an addition product of 30 to 35 mols of ethylene oxide to 1 mol of technical stearyl alcohol. The mixture is warmed to the boil over the course of 30 minutes and kept at the boil for 30 minutes. After rinsing and drying, a strong brightening effect of good fastness to light is obtained.

If instead of the polyamide-6 fabric a polyamide-66 (nylon) fabric is used, similarly good brightening effects are obtained.

What we claim is:

1. A styryl compound of the formula wherein R denotes hydrogen, alkyl with 1 to 8 carbon atoms, phenylalkyl with 1 to 4 carbon atoms in the alkyl part, phenyl, cyclohexyl, nitrile, benzyloxy, phenoxy, chlorine, sulphonic acid monoalkylamide or dialkylamide with 1 to 8 carbon atoms in the alkyl part, phenylsulphone or 1 to 4 carbon atoms containing alkylsulphone, R denotes hydrogen, alkyl with 1 to 5 carbon atoms or alkoxy with 1 to 4 carbon atoms and n represents the numbers 1 or 2.

2. A styryl compound according to claim 1, corresponding to the formula (Rdn wherein R denotes hydrogen, alkyl with 1 to 8 carbon atoms, phenylalkyl with 1 to 4 carbon atoms in the alkyl part, phenyl, cyclohexyl, alkoxy with 1 to 4 carbon atoms, benzyloxy, phenoxy, chlorine, sulphonic acid monoalkylamide or dialkylamide with 1 to 8 carbon atoms in the alkyl part, phenylsulphone or 1 to 4 carbon atoms containing alkylsulphone, R denotes hydrogen or alkyl with 1 to 5 carbon atoms and n represents the numbers 1 or 2.

3. A styryl compound according to claim 1, corresponding to the formula wherein R denotes hydrogen, alkyl with 1 to 8 carbon atoms, phenylalkyl with 1 to 4 carbon atoms in the alkyl part, phenyl, cyclohexyl, alkoxy with 1 to 4 carbon atoms, benzyloxy, phenoxy or chlorine and R represents hydrogen or alkyl with 1 to 4 carbon atoms.

4. A styryl compound according to claim 1., corresponding to the formula References Cited UNITED STATES PATENTS 3,689,481 9/1972 Scheuermann et a1.

3,697,513 10/1972 Siegrist 260--240 R ALAN L. ROTMAN, Primary Examiner C. M. S. IAISLE, Assistant Examiner US. Cl. X.R.

81 W; 117-335 T; 252-403; 260-307 D, 346.2 M

UNITED AT liT NT OFFICE- 7 CERTIFICATE O CORRECTION March 12, 1974 Patent No. 7-96 707 Dated inventofls) S-iegrist et a1.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shownbelow:

.Claim 1, Column 10, lines 40-45, change v 'o. v l -c a I: to -c a \o Nm Signed and sealed this 15th day of October 1974.

Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attest-ing Officer Commissioner of- Patents UNITED STA ES PA NT OFFICE CERTIFICATE CORRECTION March 12, 1974 Patent No. 707 I D ted Invencofls) S'iegrist et al.

It is certified that: errcr appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

,Claim 1, Column 110 lines 40-45, change.

Signed and sealed this 15th day of October 1974.

Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Commissioner of Patents Attesting Officer 7 UNITED STATESPATENT OFFICE- CERTIFICATE OF CORRECTION 3, 796,707 Dated March l2, 1974 Patent No.

Inventor(s) Siegrist et a1.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

.Claim 1, ColumnlO, lines 40-45, change II l -C t -C a O lii (R2)n Signed and sealed this 15th day of October 1974.

(SEAL)- Attest:

McCOY M. GIBSON JR. Attesting Officer:

C. MARSHALL DANN Commissioner of Patents 

